The social norms marking approach to health promotion is an environmental change strategy that targets the entire social context surrounding dating and sexual violence. Whereas community-wide social norms marketing campaigns have been successfully implemented to address a range of public health issues, research has yet to rigorously examine the efficacy of social norms marketing as a community-level change strategy for dating and sexual violence prevention. Understanding the unique contribution of social norms marketing campaigns in promoting environmental change is a vital first step to understanding their role as part of a comprehensive multi-level violence prevention approach. Results of this research will make a significant contribution to the evidence base of violence prevention by testing a comprehensive, tailored, data-based social norms marketing campaign for middle schools that addresses misperceptions of: 1) the acceptability of dating and sexual violence; 2) gender roles; 3) sexual activity; 4) sexual communication/consent; 5) support for victims; and 6) bystander intervention. Students, parents, teachers and administrators will be targeted as carriers of community misperceptions through the implementation of community-specific posters, a Lunch and Learn Teacher Training, a Social Norms Video, a Teacher Workbook, a Parent Mailing, and a Parent Information Session. A School Resource Provider will work with a teacher champion to implement the campaign and identify/address kick-back. To identify environmental moderators of program effects, the Resource Provider will work with school administrators to conduct a community readiness assessment, and document neighborhood characteristics that potentially influence dating and sexual violence, such as number of alcohol outlets and presence of highly sexualized billboards or buildings. In the Refinement and Planning Phase, stakeholder interviews, establishment of a Research Advisory Board, consultation with experts in social norms marketing, and administration of an open pilot trial will be used to refine the campaign and research procedures. In the Intervention Phase, we will conduct a group randomized trial among 30 middle schools to demonstrate efficacy of the approach in reducing rates of dating and sexual violence and promoting change in community norms over a 6-month follow-up, relative to a wait-list control. In the Analysis and Dissemination Phase, we will conduct cost-effectiveness analyses, prepare project reports, and share study findings with schools and the scientific community. Partnership between researchers and a CDC RPE-funded community agency in this research will build local capacity and ensure that the campaign is both feasible and sustainable. If deemed successful, the final products of this research will ensure that the approach can be readily implemented in middle schools as one component of a multi-level prevention approach.